The present invention relates to method for applying a marking upon elongated stock and with particular reference to an edge under a utilization of a free dye jet.
Upon longitudinally seam-welding a split tube along the adjoining edges, one conducts occasionally a follow-up test concerning the quality of the weld, or the welding zone is subjected to an annealing process. This means that certain equipment such as test equipment or annealing equipment has to be guided along that weld. In a most simple manner, this is done by operating personnel, strictly on the basis of visual observation. Another method uses a pasted-on ribbon or one ascertains the temperature profile as an indication of the location of the zone to be inspected or treated, etc.
The visual observation is, of course, the most simple mode of procedure but has proven to be unreliable. Automated equipment which has been used was also found to be unreliable, and particularly reproducability of results are rarely attainable even if the expenditure and technical complications are extensive.